The present invention is in a composition which is a thermosetting adhesive and sealant.
DE-OS No. 34 02 280 describes thermosetting adhesive and sealant compositions consisting of:
(a) 70 to 95 wt.-% polyesters with at least two carboxyl terminal groups and glass transition temperatures below 20.degree. C.; PA0 (b) 5 to 30 wt.-% polyoxazolines which are suspended in the polyesters; PA0 (c) 0 to 4 wt.-% paraffin, plus, if desired; PA0 (d) 1 to 50 wt.-% reactive or nonreactive diluents and/or additives. PA0 (a) 20 to 60 wt.-%, preferably 25 to 55 wt.-%, of carboxyl-group-terminated polyesters with a glass transition temperature below 20.degree. C.; PA0 (b) 2.0 to 12 wt.-%, preferably 3 to 8 wt.-%, of polyoxazolines which contain at least 2 oxazoline groups per molecule, the polyoxazolines being suspended in the polyesters; PA0 (c) 2 to 40 wt.-%, preferably 3 to 30 wt.-%, of acrylic or methacrylic esters, preferably of polyvalent alcohols and/or allyl esters of polyvalent carboxylic acids.sup.X including carbonic acid.sup.X, in the form, if desired, of mixtures of these compounds; FNT X=polyvalent carboxylic acid means an organic acid, preferably deriving from an alkane or an alkene, bearing two or more groups --COOH, carbonic acid means the unstable acid (HO).sub.2 C.dbd.O. PA0 (d) 0 to 5 wt.-%, preferably 0.2 to 3 wt.-%, of peroxides or aliphatic azo compounds as radical formers; PA0 (e) 0 to 4 wt.-%, preferably 0.5 to 2 wt.-%, of paraffin and, if desired, additionally; PA0 (f) 1 to 60 wt.-%, preferably 1 to 50 wt.-%, with respect to the total amount of the components, of reactive or nonreactive diluents and/or additives.
The compositions described in DE-OS No. 34 02 280 have good mechanical properties and good adherence even to steel that has not been degreased. However, the user's need for applicability at room temperature is not satisfied because the compositions are semisolid or not sufficiently liquid. If for economic reasons fillers are added, the fluidity of the adhesive paste is not sufficient even at 50.degree. to 90.degree. C. for heated spray guns, for example. Furthermore, the hot adhesive is poorly "accepted" on cold surfaces of sheet steel that has not been degreased.
Nonreactive diluents, which can be added in amounts that still do not impair the properties of the set adhesive compositions, result in adhesives whose application temperature is 50.degree. C. or higher. Reactive diluents participate in the crosslinking, having a high inherent viscosity, and thus do not improve fluidity.
The problem therefore was to develop a thermosetting binder system for use as an adhesive and sealant composition which could be applied at room temperature with any conventional applicator apparatus and which is entirely free of volatile solvents. Such a composition should also have a shelf life, adhesion and mechanical properties at least equal to those of the compositions according to DE-OS No. 34 02 280.